Machine for forming a heat transfer core structure



July 7, 1954 G. F. BAIRD 3,139,920

MACHINE FOR FORMING A HEAT TRANSFER CORE STRUCTURE Filed Dec. 9, 1960 3 Sheets-Sheet l /5 INVENTOR C @noem F. @Ruza 7t z g- E 1 BY Tl/WM@ ATTORNEY July 7, 1964 G. F. BAIRD 3,139,920

MACHINE FOR FORMING A HEAT TRANSFER -CORE STRUCTURE Filed Dec. 9, 1960 5 Sheets-Sheet 2 INVENTOR @einem F EbnV-D i BY ATTORNEY G. F. BARD July 7, 1964 MACHINE FOR FORMING A HEAT TRANSFER CORE STRUCTURE 3 Sheets-Sheet 5 Filed Dec.

INVENTOR (nonno u V. EDLHLD ATTORNEY United States Patent O stone Corporation, Jamestown, N.Y., a corporation of New York Filed Dec. 9, 1960, Ser. No. 75,032 8 Claims. (Cl. 153-2) This invention relates to a mechanism for the continuous forming of transverse folds or pleats in a strip of thin sheet metal used in heat exchange core structures. In particular, the invention is directed to a mechanism which produces a series of alternate folds or pleats that are substantially parallel and uniformly spaced and may include bumps, flutes, louvers, or other shapes common to such structures in connection with the deflection of air. Furthermore, the mechanism is designed to produce folds or pleats of desired angularity and with a predetermined number thereof per given length, thus enabling cutting and assembling such strips into core units.

Broadly, it is not new to form a ribbon-like metal strip into relatively wide or open transverse pleats, nor is it new to use some mechanism by which to compress the pleats so that the number thereof will be approximately uniform in the length of one strip with respect to another. It will, of course, be understood that the strips to which the present invention relates are of the nature of spacer or separator strips between pairs of strips or tubes which form Water passageways. In other words, the present strip not only serves to laterally space a pair of water passage strips or tubes, but is designed to so deect air passing therethrough as to create a highly eicient exchange of heat. That is, in heaters, such as may be used in the warming of cars, forced air through the folded or pleated strips will transfer a considerable measure of heat generated in the walls of the water passages to the air line.

Inasmuch as the material from which heater or other similar cores are made is extremely thin (for purposes of efficient heat transfer), the problem of producing the desired configuration in the folds or pleats is of extreme importance. Also, it is essential to produce these folds or pleats in exact duplication, strip for strip, and in such manner that the folds or pleats of any one given strip will be identical in number, depth, spacing and configuration with any other corresponding strip.

In the past it has been the practice, in mechanisms of the general nature of the present invention, to fold the metal ribbon-like strip and make use of a friction or spring loaded catch to compress the folds or pleats. The final spacing of these folds or pleats was determined by the spring back of the metal as the folds were released by the catch. Of course, this spring back was dependent on the stiffness and temper of the metal strip and also on the extent of compression produced by the friction exerted by the catch. Due to the relative lightness or thinness of the stock, the folds or pleats compress very easily until adjacent folds come into contact. Any further compression, of course, required considerable force and adjustment of the tension on the spring catch and was not @only very sensitive but also had to often be varied in the course of production to compensate for any change or difference in the thickness, stiffness, or temper of the raw material, if anywhere near uniform spacing of folds or pleats were to be produced and maintained.

It is an object of the present invention to provide a device for producing a transversely folded metal ribbon in which a predetermined number of folds or pleats are created per given ribbon length.

It is also an object of the invention to enable the initial producing of open folds or pleats in which desired flutes or louvers may be formed and subsequently compacting such folds to produce an exact number thereof per given strip length, one strip with respect to another.

It is also a Very important object of the invention to provide mechanism which, in sequence, produces relatively open, contoured, transverse folds or pleats, compacts such folds to an extent greater than required, and subsequently opens up such folds to not only provide a desired angularity of the folds, but also to enable the continuous forming of processed sheets of predetermined length and corresponding number of folds.

FIG. l is a fragmentary side elevational view, partly broken away, showing a mechanism which discloses, from left to right, the sequence of producing a heat transfer core strip;

FIG. 2 is a top plan View of the structure shown in FIG. 1;

FIG. 3 is a side elevational view, taken from the opposite side of that shown in FIG. l, and with the parts in reverse relative position;

FIG. 4 is an enlarged longitudinal vertical sectional view, taken substantially as suggested by the line 4 4 of FIG. l;

FIG. 5 is a transverse vertical sectional view, taken substantially as suggested by the line 5-5 of FIG. 4; and

FIG. 6 is a generally diagrammatic isometric view of the complete drive for the pleated strip forming mechamsm.

In conformity with the present invention, it is found desirable and expedient to run a continuous metal strip through a set or pair of mating roller dies which will not only form wide open angular folds or pleats, but will include in the surfaces of these folds or pleats, any and all desired bumps, louvers, etc., by which to deflect the iiow of air. Following this operation, it is of course necessary to close the wide open folds or pleats and, since the metal strip has a certain innate resiliency, it is necessary to compress the folds or pleats beyond that ultimately required per given sheet or strip length. Consequently, gathering means is provided which functions, Without damage to the initially formed folds, to compress these folds to an extent beyond that which is ultimately desired. Thence it is found most suitable to allow the overcompressed folds or pleats to be expanded by structure which will count or tally the folds and pleats so that at such time and by means of other structure, sections of a continuous metal sheet that has been folded to produce desired folds or pleats may be cut into given lengths. And these identical lengths will, in accordance with the invention, be found to contain exactly the same number of folds or pleats, one length with respect to another.

Attention is now more particularly directed to the invention in conjunction with the accompanying drawings wherein, as shown in FIGS. l, 2, and 3, the invention is embodied in a complete machine by which to produce folded or pleated strips of thin sheet metal for assembly into heat exchange core structures. Generally speaking, the machine is referred to by the reference numeral 10 and shows a structure 11 having roller dies 12 which, when a thin, iiat sheet of metal ribbon 13 is fed into them, produces a series of transverse corrugations, pleats or folds of the general nature suggested at 14 in FIG. 4. Due to the fact that it is old and Well known to produce folds or pleats through the use of roller forming dies of one configuration or another, such dies are no more than generally indicated in the drawings of the present disclosure. From the roller dies 12, the pleated metal strip 14 progresses to a unit 15 that is of the nature of a gathering box. Beyond this unit is a conveyor 16 which feeds the contoured and properly folded pleats to a cut-off machanism that constitutes no part of the invention. FIGS. 1 to 3, inclusive, are intended to show that a continuous Hat metal ribbon, after passing through the set of forming dies 12, enters the unit 15. This unit is a box-like structure and includes what may be termed a cage or trackway 17. This cage extends the full length of the unit and may suitably continue into the conveyor 16.

For a clearer understanding, the unit 15 may be considered as consisting of three parts; namely, a set of pusher rolls, a set of packing or gathering rolls, and a set of adjusting or expanding rolls, these parts being broadly designated as X, Y, and Z. Referring more specifically to FIG. 4, it will be noted that the relatively wide open pleated strip 14 enters the cage 17 and immediately passes between upper and lower sets of toothed rolls 1S. The rolls of each set are of the nature of sprockets and, as suggested in FIG. 2, are three in number. The lower set is carried by a shaft 19 and the upper set by a shaft 20. These shafts are properly supported in the unit 15. The rolls of each set have transverse rib-like -teeth 21, the teeth of each roll of one set alternating with the teeth of the corresponding roll of the other set in a sutliciently interftting relationship that the pleated strip will be moved longitudinally of the cage when the rolls 18 are rotated in unison, the teeth of the rolls of one set entering one of the open angles of the strip on one side and the next teeth of the rolls of the other set entering the open angle on the other side of the strip. Although both sets of rolls 18 are shown to be driven, it is not absolutely essential in advancing the strip; in fact, one set of rolls could be of the idler type or, under certain circumstances, be eliminated entirely. The whole purpose of these rolls is to assure progress of the pleated strip through the cage and at a predetermined rate of speed and, depending on the general nature of the pleat configurations, the use of one or two driving rolls may be determined.

Beyond the pusher rolls X, and projecting top and bottom into cage 17, are the packing rolls Y. As shown in the drawings, the two rolls 22 are of considerably lesser diameter than the sets of rolls 18 and include many more teeth 23 than the previously mentioned rolls. The teeth 23 of these rolls are so designed that the space or groove 24 therebetween will engage the rounded fold of each pleat. As the diagrammatic view of FIG. 6 clearly suggests, the rolls 22 are driven in time with the pusher rolls 18. Thus the condition prevails where the pleated strip is moved along the cage by rolls 18 and, as this strip is engaged by the packing rolls, a lag develops to the extent that the wide open folds of the strip are compressed or compacted. This compacting operation, which is wholly controlled by the toothed relationship of rolls 18 and rolls 22, serves to completely bend or fold the pleats so that one pleat is tightly nested with the next pleat. Thus it may be seen that up to this point the folds or pleats produced by the roller dies 12 have been compacted or gathered together to an extent that one pleat abuts another but without damage to any bumps or louvers that may have been initially formed by the roller dies.

Once the compacted folds or pleats have passed the packing rolls 22, the residual elasticity in the metal will cause the pleats to slightly expand or open. The degree of compression between rolls 18 and 22 is selected so that the natural spring back of the pleated metal strip gives a spacing between folds which is generally less than the desired finished spacing. To bring the folds or pleats into desired spacing, the pair of adjusting rolls Z are provided, being individually indicated by the reference numeral 26. These rolls are provided with teeth 27 which enter the cage 17 from top and bottom and are intended to engage the spaces between the very slightly opened folds or pleats of the strip, following its leaving the rolls 22. The teeth 27 of these rolls are wedge-shaped and, of course, the center distance between the upper and lower roll may be varied, thus varying the extent with which these wedge-shaped teeth enter the folds of the strip. It will be understood that the pitch spacing of teeth 27 on rolls 26 is predetermined and engagement thereof with the ribbon so adjusted that, as the teeth 27 engage the folds or pleats they are opened up to give the exact desired dimension; that is, a given number of folds or pleats per specified strip length.

As suggested by the dotted line structure 28 in FIG. 4, it may be found desirable to provide two sets of compacting rolls, either with the same pitch spacing of teeth or with different pitch spacing, for the purpose of obtaining the necessary lengthwise compression of the folds in two stages, or even to obtain a higher or tighter compression without distortion of the folds. It is within the sphere of the invention, where two or more pairs of compacting rolls are used, to have the teeth on one pair cut along a spiral in order to produce a slight difference in compression across the width of the strip. Such variations in the structure for moving, compacting and again expanding the folds or pleats formed by the roller dies may be found desirable due to variations in the thickness or resiliency of the metal strip 13 or to the extent to which the strip has been deformed by bumps, louvers, etc., during forming.

The substance of the invention having been described, it is believed appropriate to refer to the drive structure therefor in order that the sequence of action of the folded or pleated strip may be more readily understood and appreciated. To this end, reference is now more particularly had to FIG. 6 which is essentially an isometric diagrammatic showing of this structure. A suitable motor 30, located as suggested in FIG. 2, drives the forming rolls 12. Remote from this motor is a housing 31 which encloses one end portion of a pulley mounted belt 32. This belt, of course, within the housing 31, engages a pulley that may be geared to or directly driven by the motor 30. One end of shaft 19 that carries one of the sets of driving rolls 18, mounts a pulley 33 with which the belt 32 is engaged. At the opposite end of shaft 19 is a further pulley 34. A shaft 36, having a pulley 37, is driven through belt 38 by engagement with pulley 34 of shaft 19. It will be noted that shaft 36 mounts a gear 39 (see FIG. 4). A swing arm 41, pivotally mounted on shaft 36, carries a gear 42 which, while always in mesh with gear 39, may be moved by a suitable control rod 43 into or out of driving engagement with a gear 44 mounted on the lower shaft 45 that carries one of the adjusting rolls 26.

Again referring to the shaft 19, it will be noted that a gear 46 thereon meshes with a train of gears 47 for the purpose of driving shaft 48 on which one of the packing rolls 22 is mounted. The other packing roll 22, shown to be mounted on a shaft 49, is driven by shaft 48 through a pair of gears 51. Thus, as viewed in FIG. 6, all operative parts of the mechanism are synchronized. In other words, the, forming rolls, driving rolls, gathering rolls and adjusting rolls are all driven by the motor 30. Additionally, a pulley 40 on shaft 19 carries a belt 50 which, through pulley 53, reduction drive 54 and belt 52, enables operating suitable strip cut-off mechanism in appropriate timing with the above operative structure. Of course, it will be readily appreciated that in the manufacture of pleated strips for heat exchange structures there will be, from time to time, a difference in pleat requirements and also thickness of metal or the presence or absence of bumps or louvers in the pleats. By reason of the driving arrangement shown, the ratio of the various gears may be varied without in any way altering the spirit and scope of the invention. As already suggested, more than one gathering set of gears may be provided. Furthermore, by changing the gear ratio, due possibly to the extent of openings in the pleated strip as initially formed, it is conceivable that the gathering rolls might necessarily function in slightly different speed relation- 3 ship to either the driving rolls or the adjusting rolls. The convenience and availability of the driving mechanism for such changes or others that may be contemplated should be clearly apparent from the foregoing description of the drive.

To sum up, the continuous flat metal strip 13, fed from a suitable reel, passes through the forming rolls 12 to create the wide open transverse folds or pleats 14. In a pleated strip of the nature shown, wherein the pleats must be relatively close together for efficient heat transfer, it would be unsuitable, and in many instances, impossible, in one operation, to create many of the currently required pleated core strips. Thus, the forming rolls merely produce the Wide open pleats, With or Without bumps or louvers, as the case may be, and this pleated strip passes between the pusher rolls 18. These rolls serve to drive the pleated strip lengthwise of the cage in order that the strip may be acted on in sequence; rst, by the packing or gathering rolls, and then by the adjusting or expanding rolls. It is believed the disclosure in FIG. 4 clearly indicates that the driving rolls 18 and the gathering rolls 22 are so arranged as to relative rotation, size and number of teeth that the pleats will be compacted substantially as disclosed. As mentioned, the inherent resiliency of the metal strip will cause the compressed pleats to somewhat expand as they leave the gathering rolls. HOW- ever, since any variation in the metal strip may produce greater or lesser expansion of the pleats, at this point it is necessary to provide the adjusting rolls 26 and, of course, these rolls are so synchronized with the other sets of rolls that they will engage and open the pleats to an exact and uniform extent and, in a sense, count the number of pleats per inch. This, of course, enables the ultimate cutting of the continuous pleated strip into predetermined lengths and at the same time assuring that each length will consist of exactly the same number of pleats as any other length.

It Will be evident from the foregoing that the invention shown and described may be modied to the extent of adapting it for use in the forming of pleated strips from various metals, thicknesses thereof, number of folds or pleats per given section length, and that such modifications as may be necessary are contemplated as being Within the spirit and scope of the invention insofar as they are set out in the annexed claims.

Having thus set forth my invention, what I claim as new and for Which I desire protection by Letters Patent 1s:

1. A mechanism for fabricating a ribbon-like metal strip for use in a heat exchange core comprising an elongated cage for receiving said strip from a pair of driven forming rolls, a pair of pusher rolls projecting into said cage to engage and move said strip from one end thereof toward the other, a pair of packing rolls projecting into said cage adjacent said pusher rolls and serving to engage and compact the shapes produced by said forming rolls, and a pair of adjusting rolls projecting into said cage adjacent said packing rolls and remote from said pusher rolls, said adjusting rolls engaging said strip and serving to expand the shapes produced by said forming rolls to a predetermined extent.

2. A mechanism for fabricating a ribbon-like metal strip into transverse corrugations for use in a heat exchange core comprising an elongated cage for receiving said strip as it leaves a pair of corrugation forming rolls, a pair of pusher rolls projecting into said cage engaging the corrugations and serving to move said strip lengthwise of said cage, a pair of packing rolls projecting into said cage adjacent said pusher rolls engaging the folds of said corrugations and effecting a compaoting of said corrugations, and a pair of adjusting rolls projecting into said cage adjacent said packing rolls and remote from said pusher rolls, said adjusting rolls including teeth engageable with the compacted corrugations of said strip and serving to expand said corrugations to a predetermined extent.

3. A mechanism for the continuous fabrication of a thin ribbon-like metal strip into uniformly spaced transversely disposed folds or pleats for use in a heat exchange core comprising an elongated cage or trackway for receiving said strip as it leaves a pair of relatively open pleat forming rolls, a pair of pusher rolls having synchronized drive With said forming rolls, teeth in said pusher rolls spaced to engage the pleats of said strip and move said strip in the direction of the length of said cage, a pair of packing rolls projecting into said cage adjacent said pusher rolls, teeth on said packing rolls of lesser spacing than the teeth on said pusher rolls, the pleats of said strip being compacted on approach to said packing rolls when all of said rolls are driven at relative speed consistent with the difference in the number of teeth of one set of rolls With respect to the other, and a pair of adjusting rolls projecting into said cage adjacent said packing rolls, said adjusting rolls including teeth engageable with said pleats and serving to expand them to a predetermined extent.

4. A mechanism for fabricating transversely pleated sections of uniform length from a continuous strip of thin ribbon-like metal for use in a heat exchange core, said mechanism comprising an elongated cage or track- Way for receiving said strip as it leaves a pair of relatively open pleat forming rolls, a pair of pusher rolls having teeth spaced to engage opposite walls of said pleats and move said strip in the direction of the length of said cage, a pair of packing rolls projecting into said cage in the line of advance of said strip, said packing rolls being of lesser diameter than the diameter of said pusher rolls and including teeth engageable only with the folds defining the edges of said pleats, said pleats, when said pusher rolls and said packing rolls rotate at predetermined relative speeds, being tightly folded or compressed, a pair of adjusting rolls projecting into said cage adjacent said packing rolls and remote from said pusher rolls, said adjusting rolls including teeth engageable with and serving to expand said pleats to a predetermined extent, and means for severing said strip into sections of like length and number of pleats.

5. A mechanism for fabricating transversely pleated sections of uniform length from a continuous strip of thin ribbon-like metal for use in a heat exchange core, said mechanism comprising an elongated cage or trackway for receiving said strip as it leaves a pair of toothed rolls which have produced relatively Wide open transverse folds or pleats, a pair of pusher rolls projecting into said cage and having transverse teeth spaced to engage the Walls of said pleats, means driving said pusher rolls in a direction to move said strip a long said cage, a pair of packing rolls projecting into said cage and being adjacent to said pusher rolls in the direction of movement of said strip, the diameter of said packing rolls being less than that of said pusher rolls and including a greater number of teeth, said means driving said packing rolls at a speed consistent with the tooth spacing of the teeth of said pusher rolls whereby to effect a crowding and compressing of said pleats as said strip advances beyond said packing rolls, a pair of adjusting rolls projecting into said cage at a point beyond said packing rolls, said last mentioned rolls including relatively pointed transverse teeth engageable with the Walls of said pleats and serving, as said strip progresses through said cage, to expand said pleats to a predetermined extent.

6. A mechanism for fabricating transversely pleated sections of uniform length from a continuous strip of thin ribbon-like metal for use in a heat exchange core, said mechanism comprising an elongated cage or track- Way for receiving said strip as it leaves a pair of toothed rolls which have produced relatively wide open transverse folds or pleats, a pair of pusher rolls projecting into said cage and having transverse teeth spaced to engage the walls of said pleats, means driving said pusher rolls in a direction to move said strip along said cage, a pair of packing rolls projecting into said cage adjacent said pusher rolls, the diameter of said packing rolls being less than that of said pusher rolls and including a greater number of teeth, said means driving said packing rolls at a speed consistent with the toothL spacing of the teeth of said pusher rolls whereby to eifect a crowding and compressing of said pleats as said strip advances through and beyond said packing rolls, a pair of adjusting rolls projecting into said cage at a point beyond said packing rolls, said adjusting rolls having relatively pointed transverse teeth engageable with and serving to expand the compacted pleatsy as the strip moves beyond said compacting rolls, and manually operable means for releasing engagement of said adjusting rolls with said Strip.

7. A mechanism for fabricating transversely pleated sections of uniform length from a continuous strip of thin ribbon-like metal for use in a heat exchange core, said mechanism comprising an elongated cage or trackway for receiving said strip as it leaves a pair of toothed rolls which have produced relatively wide open transverse folds or pleats, a pair of pusher rolls projecting into said cage and having transverse teeth spaced to engage the walls of said pleats, a pair of packing rolls projecting into said cage and being adjacent to said pusher rolls in the direction of movement of said strip, the diameter of said packing rolls being less than that of said pusher rolls and including a greater number of teeth, the pitch interval of the teeth of said pusher rolls being greater than the pitch interval of the teeth of said packing rolls whereby to effect a crowding and compressing of said pleats as said strip advances beyond said packing rolls, a pair of adjusting rolls projecting into said edge at a point beyond said packing rolls, said last mentioned rolls including relatively pointed transverse teeth engageable withy the walls of said pleats and serving, as said strip progresses through said cage, to expand said pleats to a predetermined extent.

S. A mechanism for fabricating a ribbon-like metal strip for use in a heat exchange core comprising an elongated cage for receiving said strip from a pair of driven forming rolls, a pair of pusher rolls projecting into said cage to engage and move said strip from one end thereof toward the other, a pair of packing rolls projecting into said cage adjacent said pusher rolls, teeth on said pusher rolls and said packing rolls, the pitch interval of the teeth on said packing rolls being less than the pitch interval of the teeth on said pusher rolls, means driving said pusher rolls and said' packing rolls at relative speed constant with the difference in number of teeth of the roll sets whereby t0 effect a crowding and compression of the shapes produced by said forming rolls, and a pair of adjusting rolls projecting into said cage adjacent said packing rolls and remote from said pusher rolls, said adjusting rolls engaging said strip and serving to expand the shapes produced by said forming rolls to a predetermined extent.

References Cited in the tile of this patent UNITED STATES PATENTS 1,018,399 Livingston Feb. 20, 1912 2,661,946 Chambon Dec. 8, 1953 3,003,540 Robinson Oct. 10, 1961 FOREIGN PATENTS 106,894 Australia Mar. 23, 1939 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0o 3Y 139q920 July 7 1964 Gordon F1 Baird It is hereby certifiedv that error appears n the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column ZSz line 34XI for "edge" read cage Signed and sealed this 10th day of 'November l964 (SEAL) Attest:

ERNEST W. SWIDER' EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A MECHANISM FOR FABRICATING A RIBBON-LIKE METAL STRIP FOR USE IN A HEAT EXCHANGE CORE COMPRISING AN ELONGATED CAGE FOR RECEIVING SAID STRIP FROM A PAIR OF DRIVEN FORMING ROLLS, A PAIR OF PUSHER ROLLS PROJECTING INTO SAID CAGE TO ENGAGE AND MOVE SAID STRIP FROM ONE END THEREOF TOWARD THE OTHER, A PAIR OF PACKING ROLLS PROJECTING INTO SAID CAGE ADJACENT SAID PUSHER ROLLS AND SERVING TO ENGAGE AND COMPACT THE SHAPES PRODUCED BY SAID FORMING ROLLS, AND A PAIR OF ADJUSTING ROLLS PROJECTING INTO SAID CAGE ADJACENT SAID PACKING ROLLS AND REMOTE FROM SAID PUSHER ROLLS, SAID ADJUSTING ROLLS ENGAGING SAID STRIP AND SERVING TO EXPAND THE SHAPES PRODUCED BY SAID FORMING ROLLS TO A PREDETERMINED EXTENT. 